Because every criminal trial is different, criminal defense lawyers use case-specific tactics to help their clients who may be facing serious criminal charges.
A key goal of a criminal defense strategy is to counter the factual allegations made by the prosecution. For example, if the prosecutor intends to prove a defendant was at the crime scene when the crime was committed, the defense attorney could ask witnesses questions aimed at establishing the defendant was not at the scene of the crime. Any criminal defense strategy will need to be somewhat fluid, depending on how the defendant answers the prosecution's questions.
The truth is at the core of any criminal defense and a defendant must be honest with his or her defense attorney at all times. Doing so will allow the attorney to tell the defendant's story in the best light. It also allows for a truthful examination of the evidence and can help establish that the defense's version of what happened is the truth. It may also let the jury and the judge sympathize with the defendant's plight.
Defendants generally tell three kinds of story to their lawyers. The first is a confession, where the defendant admits they committed the crime. The second is complete denial where the defendant refutes all of the charges leveled by the prosecution. The final category can be called the "admit and explain" story where the defendant admits to some or all of the acts alleged by the prosecution, but believes he or she had a legitimate reason for the acts in question. Based on these conversations and a thorough review of the evidence, a defense attorney will then try to come up with the best possible defense for the client.
Source: www.findlaw.com, "Criminal defense strategies", Accessed May 25, 2015